Method and machine for generating splines and the like



June 28, 1949. w l mso I 2,474,209

METHOD AND MACHINE FOR GENERATING SPLINES AND THE LIKE Filed Feb. 18, 1944 3 Sheets-Sheet l ON 2,474,209 GENERATING LIKE June 28, 1949. J. L. W] lA METHOD AND MACH N SPLINES AND 5 Sheets-Sheet 2 Filed Feb. 18, 1944 W922i? famf.

June 28, 1949; J.

METHOD AN L. WILLIAMSON D MACHINE FOR GENERATING SPLINES AND THE LIKE Filed Feb. 18, 1944 3 Sheets-Sheet 3 be rotated, with its axis D at one side of and parallel to the position occupied by the work piece when the cutting action is performed, and a relative reciprocation is effected between the cutter and work piece in the dir'ection of the length of the work piece and of the axis of the cutter.

The work piece is mounted on a holder H, which is rotated, when in operation, about an axis E. The work piece is located at a distance greater than its own radius (preferably very much greater) from the axis E and is located relative to the cutter so that the portion of its circumference remote from the axis E is adapted to travel in an orbit (designated by the arc F), which intersects the circumference G of the cutter in which the outer extremities of the teeth t lie. The work piece is withheld from rotation about its own axis on the holder.

In the performance of the method, the holder H is progressively rotated about axis E and the cutter C rotated about its axis D at harmonious speeds such that the linear speed of the cutter teeth is equal to the linear speed of that portion of the work piece which travels in intersection with the circumferential line G. Such rotation is preferably continuous, but may be intermittent. In the course of this rotary movement of the cutter and work holder, a rapid relative reciprocating movement is effected between the cutter and work piece, whereby the cutter planes out a groove in the side of the work piece and generates the side and bottom surfaces of such groove.

It should be noted that the outlines of the cutter teeth are conjugate to the cross sectional contours of the sides of the splines to be generated and the bottoms of the intermediate grooves. Where the splines are required to have straight sides (that is, straight in planes perpendicular to the axis of the work piece), the side faces of the cutter teeth are curved with a conjugate curvature. The progress of cutting a groove between adjacent splines is indicated in Figs. 3, 4 and 5. The cutter is mounted in suitable angular relationship to its spindle and the work holder to cause one of its teeth t to reach the point of intersection between the circumferences G and F at the same time that the work piece in its travel reaches that intersection. ence to Figs. 2-5, and assuming that the cutter and holder are rotated in the directions of the arrows applied thereto, the intersection point referred to is the point K, and the cutter is so disposed that the middle radius of one of its teeth and the common radius of the holder and work piece reach the point K at the same time. Cutting commences when the advancing side of the tooth encounters the work piece (these members being then substantially in the position shown in Fig. 3), and continues while the work piece and cutter tooth cross the line of centers D-E (the position shown in Fig. 4), and until they draw apart, as shown in Fig. 5. By virtue of the planetary movement of the work piece about an axis relatively remote from its own axis, the cutter generates clean, sharp angles between the sides s of the splines and the bottoms of the grooves. That is, no fillets are left in these angles. And at the same time the desired contours of the splines extend all the way to the outside circumference of the work piece; that is, they are not rounded off at the outer extremities.

Preferably the invention includes, further,

With refermounting a large number of work pieces in a circular series around the work holder axis E, rotating the holder so as to carry the work pieces, one after the other, past the cutter and cause a groove to be cut in each, indexing each work piece after a groove has been cut in it, and continuing to circulate the work pieces through their orbit past the cutter, and index them, one or more times, until a prescribed desired number of splines have been cut. Where provision is made for thus actuating a series of work pieces, the spacing of the work pieces and the spacing of the teeth of the cutter are so correlated with one another and their relative speeds of rotation that, as each work piece approaches and crosses the line of centers D-E, a cutter tooth also approaches and crosses the line of centers in the manner and with the generative eifect precedently described. It is immaterial what the diameter and number of teeth of the cutter are, provided only that they, and the speed of rotation, are such as to produce that effect, and that the cutter teeth are suitably spaced apart to avoid simultaneous cutting of two grooves in any work piece at a greater or less distance apart than the prescribed width of a spline.

The work holder H is a turret secured to a shaft 12 which, as shown by broken lines in Fig. l, is rotatably mounted in the base of a suitable machine frame I3. The turret has a rim 14 carrying alined spaced apart centers 15 and [6 between which the work piece is held. The centers I5 are mounted in a flange l'l surrounding and integral with the rim l4, while the centers it are individually carried by separate spring retracted slides 18, one of which is shown in Fig. 7. The slide [8 as here shown is a bar fitted in a socket which enters the rim i l from the top thereof. A spring 19 surrounds the inner end portion of the slide and is confined between a head 20 on the extremity of the slide and a ring H which bears against a shoulder 22 in the walls of the socket. The slide protrudes from the upper extremity of rim l4 and to its outer end is secured a block 23 extending outwardly from the rim and in the overhanging portion of which the center I6 is secured. An arm 24 projects from the outer end of slide l8 oppositely to the block 2| and carries an adjustable stop screw 25 arranged to bear on the upper face of rim M for limiting the movement of the slide l8 inwardly and of the center 16 toward the center 45. The slide may be raised to disengage center it from the work piece when the work is to be changed. For insuring correct alinement of the center l6 with IS, a key 26 is secured to the slide and is adapted to enter a notch or keyway 2'! in the rim.

The work piece is prevented from rotating on the centers by a retractable bolt 28 fitted to slide radially in the rim M and having a tapered nose or key portion 29 on its extremity which is pressed outward by a spring 38 into a notch formed in the work piece, or in an index disk secured to the work piece, adjacent to the shoulder S or elsewhere. There are as many such notches in this part of the work piece or the index disk as the number of splines to be cut in the part W; and the bolt is adapted to enter any one of such notches. The bolt is retracted, to permit indexing of the work, by automatic means later described in connection with the indexing means.

The cutter C is secured to a spindle 3i mounted to rotate and reciprocate in a saddle 32 which velocity of the cutter tooth is equal to the linear velocity of the side of the shaft next to the cutter, and effecting a relative planing action between the cutter and shaft lengthwise of the shaft.

3. The method of generating splines in shafts without undesired curvatures, which comprises revolving a shaft in an orbit around an axis substantially parallel to its own axis, while causing a given diameter of the shaft to remain in the same radial relationship to such orbit while passing the cutter, mounting a circular gear shaper cutter at one side of such orbit in a position such that a tooth of the cutter may incise the shaft, rotating the cutter in time with the revolution of the shaft with a pitch line velocity equal to the velocity in its orbit of the side of the shaft nearer to the cutter, and reciprocating the cutter lengthwise of the shaft in the course of such relative rotation and revolution.

4. The method of generating splines and similar formations in shafts and the like, which comprises revolving such a shaft in an orbit around an axis substantially parallel to the length dimension of the shaft and causing a given diameter of the shaft to be and remain in fixed radial relation to such axis while passing in cutting relation with the after mentioned cutting tool, providing a cutting tool having a lateral tooth with cutting edges in an outline conjugate to the contour designed to be generated in the spaces between adjacent splines, rotating said tool about an axis substantially parallel to that of the orbit in which the shaft revolves so that the tooth revolves in an orbit which intersects the path of that side of the shaft which is nearest to the rotational axis of the cutter when passing the cutter, causing the linear speed of revolution of the tooth and the said nearest side of the shaft to be equal, locating the cutter with respect to its axis so that the tooth and the said nearest side of the shaft cross the line of centers between the axis of revolution of the cutter tooth and the axis of revolution of the shaft together, and reciprocating the cutter lengthwise of the shaft while crossing said line of centers.

5. In the generation of splined shafts by the gear shaping procedure with relative reciprocation between a shaping cutter and a shaft lengthwise of the latter, the new steps which comprise causing the shaft to revolve in an orbit around an axis spaced apart from its own axis while causing the same side of the shaft to face toward its axis of revolution during passage of the shaft in cutting relation with the cutter, and simultaneously rotating the cutter at a speed in generative cutting harmony with the speed at which the side of the shaft nearest to the cutter travels in its orbit.

6. A splined shaft generating machine comprising a rotatably mounted turret having a plurality of shaft holders arranged to carry a circular series of shafts with their axes parallel to the axis of the turret and with. one side of all the shafts tangent to a circumference centered on the turret axis and including means for locking the shaft so that it cannot rotate relatively to the turret, a cutter spindle mounted with its axis parallel to the turret axis and arranged to hold a gear shaper cutter with the circumference in which the teeth thereof are located substantially tangent to the before named circumference, means for rotating the spindle and turret at harmonious speeds such that the linear travel of the cutter teeth is substantially equal to the linear travel of the sides of the shafts which pass nearest to the spindle, and means for reciprocating the spindle endwise to cause planing action by means of the cutter teeth upon the shafts as the latter successively approach, cross and recede from the line of centers of the turret and spindle.

'7. A splined shaft generating machine comprising a rotatably mounted turret, means on the turret for holding shafts in a circular arrangement around the axis of the turret and with their length dimension substantially parallel to that axis, a cutter spindle adapted to carry a planing cutter of gear shaper type, releasable means on the turret for preventing rotation of the several shafts, means for reciprocating the spindle, means for rotating the turret and spindle simultaneously at correlated angular velocities, and means for successively releasing the several shafts and imparting to them, when released, an increment of angular movement about their own shafts at a point in their orbit where they are clear of engagement with the cutter.

8. A splined shaft generating machine comprising a rotatable carrier, means thereon adapted to hold a shaft at one side of the axis of the carrier with its length substantially parallel to said axis, a releasable dog engaging the shaft to prevent rotation thereof about its own axis, a gear shaper cutter mounted rotatably and reciprocatively adjacent to the path in which the shaft is carried by rotation of the carrier, means for reciprocating the cutter and for rotating the cutter and carrier in correlation to cause generative cutting by the cutter of spline faces in the shaft, and means for releasing said dog, turning the shaft about its own axis, and reengaging the dog with the shaft at a point in the orbit of the shaft where the shaft is clear of the cutter.

9. In a machine of the character described, a rotatably mounted turret, work holding centers mounted on the turret at one side of the axis of rotation thereof, spaced apart in a line extending lengthwise of said axis, a bolt mounted on the turret having an extremity projecting toward the line between said work holding centers, a spring acting on the bolt tending to force it outward, a rod mounted in the turret extending parallel to the line of said centers having an inclined surface engaged with an inclined surface of the bolt, and a stationary wedge block mounted in position to engage said rod during the rotation of the turret and move the same endwise, the rod when so moved acting to displace the bolt against the pressure of its spring.

10. The combination with the turret and other parts set forth in claim 9, of a pawl mounted in a stationary location adjacent to the exterior of the turret in position to engage a work piece held between said centers when the bolt is displaced in the manner set forth.

11. A machine for generating splines and similar formations in shafts and the like, comprising a rotatable holder, means carried by said holder for mounting a work piece thereon at a distance from, and with that portion in which a spline is to be formed in a position substantially parallel to the axis of rotation of the holder and including means for locking the shaft so that it cannot rotate relatively to the holder, a rotatable cutter spindle mounted adjacent to the orbit in which the work piece is revolved by said holder, a planing cutter mounted on said spindle having a tooth projecting laterally from the spindle axis with cutting edges at one end in an outline conjugate to the adjacent sides of, and the surface between,

two splines to be generated, said tooth being located to rotate in an orbit which intersects the orbit in which the outer side of the work piece revolves when the holder is rotated, means for simultaneously rotating the work holder and cutter spindle at angular speeds and in directions so related that the outer extremity of the cutter tooth and a point within the outer side of the work piece travel at the same linear speed and in the same direction when crossing the line of centers of the work holder and spindle, and means for reciprocating the cutter spindle endwise during the traverse of the cutter tooth and work piece between the points at which their respective orbits intersect.

JAMES L. WILLIAMSON.

10 REFERENCES CITED The following referenlces are of record in the file of this patent: 

